/*
 * Copyright 2002-2017 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.expression.spel.standard;

import org.springframework.lang.Nullable;

/**
 * Holder for a kind of token, the associated data and its position in the input data
 * stream (start/end).
 *
 * @author Andy Clement
 * @since 3.0
 */
class Token {

    TokenKind kind;

    @Nullable
    String data;

    int startPos;  // index of first character

    int endPos;  // index of char after the last character


    /**
     * Constructor for use when there is no particular data for the token
     * (e.g. TRUE or '+')
     *
     * @param startPos the exact start
     * @param endPos the index to the last character
     */
    Token(TokenKind tokenKind, int startPos, int endPos) {
        this.kind = tokenKind;
        this.startPos = startPos;
        this.endPos = endPos;
    }

    Token(TokenKind tokenKind, char[] tokenData, int startPos, int endPos) {
        this(tokenKind, startPos, endPos);
        this.data = new String(tokenData);
    }


    public TokenKind getKind() {
        return this.kind;
    }

    public boolean isIdentifier() {
        return (this.kind == TokenKind.IDENTIFIER);
    }

    public boolean isNumericRelationalOperator() {
        return (this.kind == TokenKind.GT || this.kind == TokenKind.GE || this.kind == TokenKind.LT ||
                this.kind == TokenKind.LE || this.kind == TokenKind.EQ || this.kind == TokenKind.NE);
    }

    public String stringValue() {
        return (this.data != null ? this.data : "");
    }

    public Token asInstanceOfToken() {
        return new Token(TokenKind.INSTANCEOF, this.startPos, this.endPos);
    }

    public Token asMatchesToken() {
        return new Token(TokenKind.MATCHES, this.startPos, this.endPos);
    }

    public Token asBetweenToken() {
        return new Token(TokenKind.BETWEEN, this.startPos, this.endPos);
    }


    @Override
    public String toString() {
        StringBuilder s = new StringBuilder();
        s.append("[").append(this.kind.toString());
        if (this.kind.hasPayload()) {
            s.append(":").append(this.data);
        }
        s.append("]");
        s.append("(").append(this.startPos).append(",").append(this.endPos).append(")");
        return s.toString();
    }

}
